Originally Posted by Riot

I use Nightshrike in my threat set, or whenever I feel like I need a touch more hit/expertise, but for "serious" stuff, I switch over to the Teron gun, of course.

I think there's three main tanking ranged slot items:

[Nightstrike]
[Gyro-Balanced Khorium Destroyer] (Still great to carry around because of the socket)
[Rifle of the Stoic Guardian]

With these three, you're set!